Performance evaluation of polymer/clay nanocomposite thermal protection systems based on polyethylene glycol phase change material

Phase change materials (PCMs) are substances with a high heat of fusion which, through melting and solidifying at specified temperatures, are capable of storing or releasing a large amount of thermal energy. This phenomenon can be utilized in designing the heat protective materials as well as in the thermal energy storage systems. In this work, effects of polyethylene glycol (PEG) as PCM and montmorillonite nanoclay, as a thermal property modifier in epoxy resin on the thermal protection performance of nanocomposites were studied. A special performance evaluation test was designed to study the top surface temperature behavior of prepared samples under back surface heating. Results indicated that increasing PCM content improved thermal protection performance, but lower thermal diffusivity was found for the sample containing 60 wt% of PEG, with a 31 % decrease in top surface temperature. These results show that increasing of top surface temperature of samples containing PCM was very slow when compared with the neat epoxy sample. A top surface temperature behavior of these samples shows a plateau in melting region of PCM which makes a delay time in temperature increment compared with that of the neat epoxy sample. Moreover, heat protection performances of low filled nanocomposite blends, i.e., nanocomposite blends with 5 and 7 wt% of clay in PEG have been improved about 10 % in comparison with EP/PEG60 blend.